The techniques of this disclosure relate to determining an optical characteristic of a camera. The device includes a housing that receives a test fixture retaining a camera. The housing includes a first segment and a second segment creating a chamber surrounding the camera. The first segment is attached to the test fixture and defines a first orifice located in a side of the first segment. The first orifice directs a flow of a gas out of the chamber. The second segment defines a second orifice located in a first side of the second segment to direct the flow of the gas into the chamber. An aperture is located in a second side of the second segment and positioned opposite the test fixture to define a field of view that includes a camera target. The aperture receives a lens barrel of the camera and enables the determination of the optical characteristic.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The device of claim 1, wherein a fitting is attached to the second segment being configured to direct the flow of the gas through the second orifice, and wherein an angle of the fitting is about 90 degrees relative to the first side.
3. The device of claim 2, wherein the fitting comprises a lip configured to rotatably retain a hose being configured to deliver the gas to the fitting.
4. The device of claim 1, wherein an area of the first orifice is equal to the area of the second orifice.
5. The device of claim 1, wherein at least two sides of the first segment are arranged at 45-degree angles relative to the inlet flow direction.
6. The device of claim 1, wherein walls of the housing are configured to circulate the flow of the gas around the camera before exiting the chamber.
7. The device of claim 1, wherein an optical axis of the camera defines a rotational axis of the test fixture, and wherein the housing is configured to rotate with the test fixture through an angle of at least ninety degrees.
8. The device of claim 7, wherein the rotational axis defines a plane parallel to the inlet flow direction, and wherein the second orifice and the first orifice are located on a same side of the plane.
9. The device of claim 8, wherein the second orifice and the first orifice are positioned at different elevations relative to the test fixture.
10. The device of claim 1, wherein the first segment and the second segment comprise insulation layers attached to one or more of internal and external surfaces.
11. The device of claim 1, wherein the field of view is in a range of about fifty degrees to about 120 degrees.
12. The device of claim 1, wherein the aperture is further defined by a conical section attached to the second segment that protrudes into the chamber toward the test fixture, the conical section defining an annulus between the lens barrel and a leading edge of the conical section.
13. The device of claim 12, wherein the annulus is in a range from about one millimeter to about fifteen millimeters.
14. The device of claim 1, wherein the optical characteristic of the camera is a modulation transfer function (MTF).
16. The device of claim 15, wherein the processor is further configured to determine the optical characteristic when the camera-temperature set point is in a range from −40 degrees Celsius to 85 degrees Celsius.
18. The method of claim 17, further comprising determining the optical characteristic, with the processor, when the camera-temperature set point is in a range from −40 degrees Celsius to 85 degrees Celsius.
19. The method of claim 18, further comprising adjusting the camera-temperature set point from room temperature to −40 degrees Celsius or from room temperature to 85 degrees Celsius in a time of about fifteen minutes to about twenty minutes.
20. The method of claim 19, further comprising holding the temperature of the camera at the camera-temperature set point for a period of at least ten minutes.
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March 16, 2021
June 6, 2023
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